A liquid crystal display panel is provided with a TFT substrate provided with a thin film transistor (also referred to as a “TFT” below), a pixel electrode, and the like for each sub-pixel, which is the smallest image unit, an opposite substrate provided opposite to the TFT substrate and provided with a common electrode and the like, and a liquid crystal layer sealed between the TFT substrate and the opposite substrate, for example. The liquid crystal display panel is configured to display images by changing the orientation of the liquid crystals in the liquid crystal layer for each sub-pixel by applying a prescribed voltage via each TFT to the liquid crystal layer for each sub-pixel interposed between the pixel electrodes of the TFT substrate and the common electrode of the opposite substrate, and thereby adjusting, for each sub-pixel, the transmittance of light radiated from a backlight provided externally.
In the semiconductor layer from which the TFT is configured, if light from the backlight is incident thereon, for example, then a leakage current is generated in the off state due to photoexcitation, which causes an increase in off current in the TFT. This results in a decrease in display quality in the liquid crystal display panel, and therefore, in the TFT substrate, the semiconductor layer of the TFT needs to be sufficiently shielded from light by a light-shielding layer.
For example, Patent Document 1 discloses exposing the entire surface of a semiconductor active layer to light from a glass substrate side and patterning the semiconductor active layer so as to be self-aligned using a light-shielding film when patterning the semiconductor active layer using photoresist, in a manufacturing method for a liquid crystal display panel provided with an insulating film, a gate electrode, a gate insulating film, and a semiconductor active layer on the light-shielding film, which corresponds to the above-mentioned light-shielding layer.